Engineered wood is in the spotlight this month as restoration experts work to determine the best way to rebuild the iconic Notre Dame Cathedral in Paris, which was devastated by fire on April 15th. Much of the 850-year-old cathedral was lost to the inferno, including wood from more than 1,300 ancient oak trees that were already 200-300 years old when felled back in the 12th century.
These old growth timbers played a crucial role in supporting the cathedral’s high vaulted ceilings. The logs that weren’t damaged by fire became waterlogged during the process of extinguishing the blaze. Sourced from over 50 acres of primary forests that have long since disappeared in Europe, these trees are a lot harder to find nowadays. That means France will have to look to other options.
Some experts say structurally engineered wood might fit the bill. Innovative new wood products can supply similar strength and size, and could also reduce the weight of the roof. The choice would be in line with recent global trends toward large-scale wooden architecture in major urban areas.
French president Emmanuel Macron says he wants the work to be done within the next five years, in time for Paris to host the 2024 Summer Olympics, a timeline that will require thousands of carpenters, craftsmen, masons and other workers. A competition to redesign the cathedral is already soliciting entries from around the world, some of which faithfully reproduce its original shape and others that radically reimagine it.
Architect Vincent Callebaut’s design for a new interpretation of the Notre Dame Cathedral is made of cross-laminated timber beams, paying homage to the original geometry in a modernized silhouette. It’s also an energy positive building, producing more energy than it consumes, and its roof is reimagined as a farm.
“The wooden frame is covered in three-dimensional crystal glass subdivided into faceted diamond-shaped elements. Consisting of an organic active layer, this cocktail of carbon, hydrogen, nitrogen, and oxygen will absorb light and transform it into power. The energy, stored within hydrogen fuel cells, will be directly redistributed throughout the cathedral.”